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    The limnological survey of a coastal lagoon in Korea: Lake Hwajinpo

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    Physicochemical parameters, plankton biomass, and sediment were surveyed from 1998 to 2000 on two months interval in a eutrophic costal lagoon (Lake Hwajinpo, Korea) segregated from the sea by a sand dune. Littoral zone is well developed and floating-leaved aquatic plants also thrive, A shallow sill divides the lake into two basins. It has permeation of seawater and chemoclines formed by salinity were observed at 1m demth all the year around. DO was often very low(<1mgO₂/L) at hypolimnion. Temperature inversions were observed in November. Transparency was 0.2~1.7m. Nitrate and ammonium concentrations were very low (<0.1mgN/L), even though TN was usually 2.0~3.5mgN/L. TN/TP was generally lower than the Redfield ratio. TSI was 63~74, COD, TP, and TN of sediment were 3.1~40.3mgO₂/g, 0.9~1.39mg/m³. Two basins showed different phytoplankton communities with Oscillatoria sp., Trachelomonas sp., Schiaochlarnys gekatinosa, and Anabaena spiroides dominant in South basin, and with Trachelomonas sp., Schroederia sp., Schizochlamys felatinosa, and Trachelomonas sp. dominant in the North basin. The seasonal succession of phytoplankton was very fast, possibly due to sudden changes in physical characteristics such as wind, turbidity, salinity and light, etc.Article信州大学山地水環境教育研究センター研究報告 2: 127-130(2004)departmental bulletin pape